Head suspension for a disk device, disk device and head IC testing method

ABSTRACT

This invention relates to a head suspension with a head IC and makes it possible to simplify checking of the head IC and reduce the cost of the head suspension. A first connection terminal  21  that electrically connects to the head  4;  a second connection terminal  22  that connects to external circuits; third and fourth connection terminals  23, 24  that electrically connect to the head IC  20,  which processes the electrical signal from the head; a first conductive path  28  that connects the first connection terminal  21  with the third connection terminal  23;  a second conductive path  26  that connects the second connection terminal  22  with the fourth connection terminal  24;  and a measurement terminal  25  that is located between the second connection terminal  22  and fourth connection terminal  24  are formed on the head suspension  9.  With this invention, contact of the probes for checking the head IC when the head IC has been installed before installing the head becomes easier.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a head suspension for supporting a headof a disk device, to a disk device which uses it, and to a testingmethod for a head IC.

[0003] 2. Description of the Related Art

[0004] Disk devices for reading a disk storage medium using a head arewidely used. For example, magnetic disk drives that are used as storagedevices for computers comprise a magnetic disk, a spindle motor thatrotates the magnetic disk, a magnetic head for reading from or writingto the magnetic disk, and a VCM actuator that positions the magnetichead at a track on the magnetic disk.

[0005] The storage density of these kinds of disk drives is greatlyincreasing, as well as is the density of tracks on the magnetic disk. Itis especially possible to increase the density by using a MR (GMR, TMR)head as the magnetic head. Therefore, high precision device is alsodesired for processing of the head signal.

[0006] In a magnetic disk device, the magnetic head is supported by asuspension. The suspension is attached to the carriage arm of a VCMactuator. The suspension has springiness and functions such that themagnetic head follow the surface of the magnetic disk. The magnetic headperforms input/output of an analog signal, so it is equipped with a headIC for processing the analog signal. The head IC comprises a preamp foramplifying the read signal of the magnetic head, and a writing amp forsupplying writing current to the magnetic head.

[0007] Normally, this head IC is attached to the carriage arm located atthe rear of the suspension. Moreover, the head IC is connected to themagnetic head by lead wires on the suspension. However, in the case of aweak magnetic head output, as in the case of the recent MR heads, it isnot possible to ignore the effect of noise that mixes into the long leadwire.

[0008] In addition, when the lead wire is long, the rising time andfalling time of the pulse signal (writing pulse) becomes longs, so thereis a problem in that it becomes difficult to transfer data at highspeed. Therefore, it is proposed to place the head IC chip on thesuspension in order to shorten the distance between the magnetic headand the head IC.

[0009] With that kind of construction, it is necessary to test eachsuspension. Conventionally, a slider on which the head IC and magnetichead are located is attached to the suspension to form a HGA (headgimbal assembly), then this HGA is made to float above the disk mediumand by the head magnetically reading/writing, the operation of the headIC and the connection status are checked.

[0010] However, with the prior method, the head and head IC of the HGAunit are checked together so when one is determined to be faulty thatfully HGA becomes faulty. Therefore, there is a problem that yielddecreases and it is difficult to keep costs down.

SUMMARY OF THE INVENTION

[0011] The objective of the invention is to provide a head suspension, adisk device and a testing method for testing the head IC installed inthe suspension.

[0012] Another objective of the invention is to provide a headsuspension, a disk device and a testing method for simply testing thehead IC installed in the suspension.

[0013] A further objective of the invention is to provide a headsuspension, a disk device and a testing method for testing the head ICthat improves the yield of the head assembly.

[0014] In order to accomplish these objectives, the head suspension ofthis invention comprises: a first connection terminal that electricallyconnects to a head; a second connection terminal that connects toexternal circuits; third and fourth connection terminals thatelectrically connect to a head IC for processing an electrical signalfrom the head; a first conductive path that connects the firstconnection terminal with the third connection terminal; a secondconductive path that connects the second connection terminal with thefourth connection terminal; and a measurement terminal that is locatedbetween the second connection terminal and fourth connection terminal ofthe second conductive path, and which is for measuring the head IC.

[0015] Moreover, the disk device of this invention comprises: a head forat least reading a disk medium, a head IC that processes the electricalsignal from the head, a head suspension which contains the head IC andwhich supports the head, and an actuator that supports the headsuspension and moves the head with respect to the disk medium; and wherethe head suspension comprises: a first connection terminal forelectrically connecting to the head, a second connection terminal forconnecting to external circuits, third and fourth connection terminalsfor electrically connecting to the head IC, a first conductive path thatconnects the first and third connection terminals, a second conductivepath that connects the second and fourth connection terminals, and ameasurement terminal that is located between the second connectionterminal and fourth connection terminal of the second conductive path,and which is for measuring the head IC.

[0016] Furthermore, the testing method for head IC of this inventioncomprises: a step of installing a head IC for processing the electricsignal from the head, and a step of placing a probe on the headsuspension terminal to test the electric characteristics of the head IC.

[0017] In this invention, first a head IC is installing on the headsuspension and the head IC is checked before installing the head. Bydoing this, it is possible to check the operation and connection of thehead IC itself, and to divide the head assembly into good or faultyparts before installing the head. Therefore, it is possible to increasethe yield and to keep down costs of the head assembly.

[0018] Second, in order to check the head IC that is installed on thesuspension, it is necessary to place a measurement probe on theterminal. Theoretically, by placing the probe on the first and secondterminals instead of the third and fourth terminals installed on thehead IC, it is possible to check the head IC. However, the secondterminal for external connection is located in a position that is easyfor external connection and it is not easy to place a probe on it.Therefore, in this invention, a measurement terminal is located betweenthe second and fourth connection terminals.

[0019] This makes contact with the probe easy and makes it possible toquickly check the head IC.

[0020] Moreover, in the head suspension of this invention, themeasurement terminal and the first connection terminal are located suchthat they are on the same plane as the suspension, and this makes iteven easier for contact with a pair of probes, which makes it possibleto check the head IC even more quickly.

[0021] In addition, in the head suspension of this invention, the first,second, third and fourth connection terminals, the first and secondconductive paths, and the measurement terminal are formed using athin-film pattern on the base of the suspension, so the measurementterminal can be formed with the same process as the other terminals andconductive paths, making construction more simple.

[0022] Furthermore, in the head suspension of this invention, flexiblecable is used around the base of the head suspension, which is providedthe first, second, third and fourth connection terminal, the first andsecond conductive paths and the measurement terminal so it is possibleto separate the base and the cable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a top view of the disk device of an embodiment of theinvention.

[0024]FIG. 2 is a cross-sectional view of the disk device in FIG. 1.

[0025]FIG. 3 is an enlarged view of the main parts of the disk device inFIG. 2.

[0026]FIG. 4 is a block diagram of the disk device in FIG. 1.

[0027]FIG. 5 is a pictorial view of the head suspension of an embodimentof the invention.

[0028]FIG. 6 is a schematic view of the head IC checking device of anembodiment of the invention.

[0029]FIG. 7 is a drawing explaining the head IC checking method of anembodiment of the invention.

[0030]FIG. 8 is a pictorial drawing of the head suspension of anotherembodiment of the invention.

[0031]FIG. 9 is a pictorial drawing of the head suspension of yetanother embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The embodiments of this invention will be explained below in theorder: disk device, head suspension and testing method, and otherembodiments.

[0033] Disk Device

[0034]FIG. 1 is a top view of the disk device of an embodiment of theinvention, FIG. 2 is a cross-sectional view of that disk device, andFIG. 3 is an enlarged view of the part in FIG. 2. In this example, ahard disk drive is used as the disk device.

[0035] As shown in FIG. 1 and FIG. 2, the magnetic disk 6 comprises amagnetic recording layer formed on a base plate (disk). The magneticdisk 6 has a diameter of 3.5 inches, and there are three disks installedinside the drive. A spindle motor 5 supports the magnetic disk 6 androtates it. A magnetic head (slider) 4 is installed on the actuator. Theactuator comprises a rotating-type VCM (voice coil motor) 3, a carriagearm 8 and suspension 9. The magnetic head 4 is installed on the tip ofthe suspension 9.

[0036] The magnetic head 4 reads data from or writes data to themagnetic disk 6. The magnetic head 4 comprises a slider that has a MRelement (reproduction element) and writing element. The actuator 3positions the magnetic head 4 at a desired track on the magnetic disk 6.The actuator 3 and spindle motor 5 are installed to the drive base 2. Acover 1 covers the drive base 2 and separates the inside of the drivefrom the outside. A printed-circuit board 7 is located below the drivebase 2 and it contains the drive control circuit. A connector 10 islocated below the drive base 2 and it connects the control circuit withthe outside.

[0037] As shown in the enlarged view of FIG. 3, the magnetic head 4 andhead IC chip 20 are placed on one side of the suspension 9. The rear endof the suspension 9 is attached to the carriage arm 8 with a pin 50. Anexternal-connection terminal 22 (described later using FIG. 5) on thesuspension 9 is guided by the surface on the side of the carriage arm 8.Therefore, the suspension 9 is fastened to the carriage arm 8.

[0038] In addition, the external-connection terminal 22 is connected toa flexible cable (not shown in the figure) in order to connect withexternal circuits. This flexible cable is located on the side of thecarriage arm 8. Moreover, since the external-connection terminal 22 islocated on the side of the arm 8, it can be connected without theflexible cable having to bend.

[0039]FIG. 4 is a block diagram of the control circuit on theprinted-circuit board 7 and inside the drive. An HDC (hard diskcontroller) 18 generates control signals inside the magnetic disk devicefor controlling the interface with the CPU for receiving commands ordata from the host CPU, and for controlling the read/write format on themagnetic disk medium. A buffer 17 is used for temporarily storing writedata from the host CPU to be written to the magnetic disk medium, or fortemporarily storing read data that is read from the magnetic diskmedium.

[0040] A MCU (micro controller) 19 comprises a microprocessor (MPU),memory, DA converter, and AD converter. The MCU (called MPU below) 19performs servo control (positioning control) for positioning themagnetic head. The MPU 19 executes a program stored in memory,recognizes the position signal from the servo demodulation circuit 16,and calculates the control amount of the VCM control current of theactuator for positioning. Furthermore, the MPU 19 controls the drivingcurrent of the SPM drive circuit 14.

[0041] The VCM drive circuit 13 comprises a power amp for causingdriving current to flow to the VCM (voice coil motor). The SPM drivecircuit 14 comprises a power amp for causing driving current to flow tothe spindle motor (SPM) 5 that rotates the magnetic disk 6.

[0042] A read channel 15 is a circuit for performing reading or writing.The read channel 15 comprises a modulation circuit for writing writedata from the host CPU to the magnetic disk medium 6, aparallel-to-serial conversion circuit, a demodulation circuit forreading data from the magnetic disk medium 6, and a serial-to-parallelconversion circuit. A servo demodulation circuit 16 is a circuit fordemodulating a servo pattern that is written on the magnetic diskmedium, and it outputs a position signal to the MPU 19.

[0043] Furthermore, inside the drive HDA, there is a head IC 20 (seeFIG. 3) which comprises a writing amp, that supplies writing current tothe magnetic head 4, and a preamp, that amplifies the reading voltagefrom the magnetic head 4.

[0044] Here, an example of a magnetic disk device is explained as thedisk device, however, it is also possible to use an optical disk devicesuch as a DVD or MO. Also, here a device that is capable of reading andwriting was used, however it is also possible to use a read-only device.

[0045] Head Suspension and Testing Method

[0046]FIG. 5 is a pictorial view of the head suspension of an embodimentof the invention, and it shows a magnetic head suspension 9.

[0047] The suspension base 27 is formed from stainless steel or thelike. There is a thin film pattern that is formed from the insulationlayer on the base 27. This thin film pattern comprises: a firstconnection terminal 21 for electrically connecting with the magnetichead 4; a second connection terminal 22 for connecting to externalcircuits; third and fourth connection terminals 23, 24 for electricallyconnecting to the head IC that processes the electrical signal from themagnetic head; a first conductive path 28 that connects the firstconnection terminal 22 and the third connection terminal; a secondconductive path 26 that connects the second connection terminal 22 andthe fourth connection terminal 24; and a measurement terminal 25, thatis located between the second terminal 22 and fourth connection terminal24 on the second conductive path 26, and is for measuring the head IC20.

[0048] The sections of the base 27 except these terminals 21, 22, 23, 24and 25 are covered by a protective layer. Also, there is hole 29 formedin the suspension 9 through which the pin 50 shown in FIG. 3 isinserted.

[0049]FIG. 6 is a schematic diagram of the testing device of anembodiment of the invention, and FIG. 7 is a drawing explaining thetesting method.

[0050] As shown in FIG. 6, the testing device comprises a receivingcradle 30 for receiving the suspension 9, a measurement head 31 with apair of probes 32, and a connector 33 for connecting to a currentwaveform measurement device (not shown in the figure).

[0051] The testing method will be explained. First, a head IC chip 20 isplaced on the suspension 9 shown in FIG. 5. For example, the head ICchip 20 is attached and connected to the third and fourth connectionterminals 23, 24 on the suspension 9. In this way, as shown in FIG. 7, aplurality of suspensions 9 with the head IC chips 20 are placed in thereceiving cradle 30 shown in FIG. 6.

[0052] As shown in FIG. 7, the measurement head 31 is lowered, a pair ofprobes 32 are brought into contact with the first head connectionterminal 21 and the IC check terminal 25 on the suspension 9, andmeasurement current from the probes 32 is output to the a currentwaveform measurement device (not shown in the figure).

[0053] The head IC chip 20 comprises at least a reading amp and writingamp. A representative example could be TLS26A803 and TLS26A801 (modelname) amps manufactured by TI. It is possible to check the operatingstate of these head IC chip amps, the diode characteristics (VIcharacteristics) and the connection status.

[0054] In this way, since the head IC 20 is placed on the headsuspension 9 and checked before installing the head 4, it is possible tocheck the operation and connection of the head IC 20 itself, and thus itis possible to divide the head assembly into good and faulty partsbefore installing the head 4. Therefore, it is possible to increaseyield while keeping down costs of the head assembly.

[0055] Moreover, in order to check the head IC 20 on the suspension 9,it is necessary for the measurement probes 32 to come in contact withthe terminals. It is possible to check the head IC 20 by bring theprobes 32 in contact with the first terminal 21 and second terminal 25instead of the third and fourth terminals on the head IC. However, thesecond connection terminal 25 for external connection is located in aposition that is easy for external connection (to the side of thesuspension 9 in FIG. 5) and it is not easy to place a probe 32 on it.Therefore, in this invention, a measurement terminal 25 is locatedbetween the second and fourth connection terminals 22, 24. This makescontact with the probe 32 easy and makes it possible to quickly checkthe head IC.

[0056] Furthermore, in the head suspension of this invention, themeasurement terminal 25 and the first connection terminal are on thesame plane of the suspension 9. In this way it is even easier forcontact with the pair of probes 32, which makes it possible to check thehead IC 20 even more quickly.

[0057] In addition, in the head suspension 9 shown in FIG. 5, the first,second, third and fourth connection terminals 21, 23, 24, 22, the firstand second conductive paths 26, 28, and the measurement terminal 25 areformed using a thin-film pattern on the suspension base 27. Therefore,the measurement terminal 25 can be formed with the same process as theother terminals and conductive paths, making construction more simple.

[0058] Other Embodiments

[0059]FIG. 8 is a pictorial view of ahead suspension of anotherembodiment of the invention, and parts that are identical to parts shownin FIG. 5 are indicated with the same symbol.

[0060] As shown in FIG. 8, the head suspension 9 comprises a headsuspension base 27 and flexible cable 40 with a first, second, third andfourth connection terminals 22, 23, 24, 25, first and second conductivepaths 26, 28, and a measurement terminal 25.

[0061] A load beam 41 and gimbal 42 are formed on the base 27. Thisexample, shows the application of a suspension 9 with a separate base 27and cable 40.

[0062]FIG. 9 is a pictorial view of a head suspension of yet anotherembodiment of the invention, and parts that are identical to parts shownin FIG. 5 and FIG. 8 are indicated with the same symbol.

[0063] As shown in FIG. 9, the head suspension 9 comprises a headsuspension base 27 and a flexible cable 40 with a first, second, thirdand fourth connection terminals 22, 23, 24, 25, first and secondconductive paths 26, 28, and a measurement terminal 25.

[0064] A load beam 41 is formed in the base 27 and a flexure 43 having agimbal 42 is attached to the base 27. This example also shows theapplication of a suspension 9 with a separate base 27 and cable 40.

[0065] In addition to embodiments described above, the invention can bechanged as follows.

[0066] (1) An example is given of placing the head IC on one side of thesuspension, however it is possible to place the head IC on both sides.

[0067] (2) Instead of a magnetic head, the invention can be applied to asuspension with an optical head or magneto-optical head.

[0068] The preferred embodiments of the present invention have beenexplained, however the invention is not limited to these embodiments andcan be embodied in various forms within the scope of the presentinvention.

[0069] As described above, this invention has the following effect.

[0070] First, the head IC is placed on the head suspension and checkedbefore installing the head. By doing so, it is possible to check theoperation and connection of the head IC itself, and thus it is possibleto divide the head assembly into good and faulty parts before installingthe head. Therefore, it is possible to increase yield while keeping downcosts of the head assembly.

[0071] Second, a measurement terminal is located between the second andfourth connection terminals in order to check the head IC on thesuspension. This makes contact with the probe easy, and makes itpossible to quickly check the head IC.

What is claimed is:
 1. A head suspension of a disk device that supportsa head for at least reading a disk medium and comprising: a firstconnection terminal that electrically connects to said head; a secondconnection terminal that connects to external circuits; third and fourthconnection terminals that electrically connect to a head IC, whichprocesses an electrical signal from said head; a first conductive paththat connects said first connection terminal with said third connectionterminal; a second conductive path that connects said second connectionterminal with said fourth connection terminal; and a measurementterminal that is located between said second connection terminal andsaid fourth connection terminal of said second conductive path, andwhich is for measuring said head IC.
 2. The head suspension of claim 1wherein; said measurement terminal and said first connection terminalare located such that they are on the same plane of said suspension. 3.The head suspension of claim 1 wherein; said first, second, third andfourth connection terminals, said first and second conductive paths, andsaid measurement terminal are formed using a thin-film pattern on thebase of said suspension.
 4. The head suspension of claim 1 furthercomprising: a base for said head suspension; and a flexible cable onwhich said first, second, third and fourth connection terminal, saidfirst and second conductive paths and said measurement terminal areformed.
 5. The head suspension of claim 1 wherein said first connectionterminal is electrically connected to a magnetic head.
 6. A disk devicecomprising: a head for at least reading a disk medium; a head IC thatprocesses an electrical signal from said head; a head suspension whichsupports said head and which contains said head IC; and an actuator thatsupports said head suspension and moves said head with respect to saiddisk medium; wherein said head suspension comprises: a first connectionterminal for electrically connecting to said head; a second connectionterminal for connecting to external circuits; third and fourthconnection terminals for electrically connecting to said head IC; afirst conductive path that connects said first and third connectionterminals; a second conductive path that connects said second and fourthconnection terminals; and a measurement terminal that is located betweensaid second connection terminal and said fourth connection terminal ofsaid second conductive path, and which is for measuring said head IC. 7.The disk device of claim 6 wherein; said measurement terminal and saidfirst connection terminal are located such that they are on the sameplane of said suspension.
 8. The disk device of claim 6 wherein; saidfirst, second, third and fourth connection terminals, said first andsecond conductive paths, and said measurement terminal are formed usinga thin-film pattern on the base of said suspension.
 9. The disk deviceof claim 6 further comprising: a base for said head suspension; and aflexible cable on which said first, second, third and fourth connectionterminal, said first and second conductive paths and said measurementterminal are formed.
 10. The disk device of claim 6 wherein said headcomprises a magnetic head.
 11. A testing method for a head ICcomprising: a step of installing a head IC for processing an electricsignal from a head for at least reading a disk medium, on a headsuspension that supports said head; and a step of placing a probe on aterminal of said head suspension to check electric characteristics ofsaid head IC.
 12. The testing method of claim 11 wherein said headsuspension comprises: a first connection terminal for electricallyconnecting to said head; a second connection terminal for connecting toexternal circuits; third and fourth connection terminals forelectrically connecting to said head IC; a first conductive path thatconnects said first and third connection terminals; a second conductivepath that connects said second and fourth connection terminals; and ameasurement terminal that is located between said second connectionterminal and said fourth connection terminal of said second conductivepath, and which is placed said probe.
 13. The testing method of claim 11wherein; said measurement terminal and said first connection terminalare located such that they are on the same plane of said suspension. 14.The testing method of claim 11 wherein; said first, second, third andfourth connection terminals, said first and second conductive paths, andsaid measurement terminal are formed using a thin-film pattern on thebase of said suspension.
 15. The testing method of claim 11 furthercomprising: a base for said head suspension; and a flexible cable onwhich said first, second, third and fourth connection terminal, saidfirst and second conductive paths and said measurement terminal areformed.
 16. The testing method of claim 11 wherein said head comprises amagnetic head.
 17. A manufacturing method for a HGA comprising: a stepof installing a head IC for processing an electric signal from a headfor at least reading a disk medium, on a head suspension that supportssaid head; a step of placing a probe on a terminal of said headsuspension to check electric characteristics of said head IC; and a stepof installing a head on said head suspension with said head IC.